Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Trying to explain to non-engineers that it may be OVERKILL, but it is NECESSARY 38

Status
Not open for further replies.

Forgot2Yield

Industrial
Feb 10, 2022
65
I constantly here non-engineers complaining about how everything structural engineers design is so unnecessary and overkill. It is hard to explain to someone unfamiliar with design codes and engineering theory why certain members need to be sized the way they are sized even if using a smaller member (or no member at all) would not cause the structure to fall down.

I am wondering if anyone has had any discussions with members of the non-engineering community around this topic, and how you explained to them that the seemingly unnecessary sizes of the components are indeed necessary.

My personal explanation includes three main reasons. Please add to this if you have more.

1) Proof
any design that you come up with, you have to be able to show or prove what the forces in the members will be. and If you don't have all the information to start out with (ex. proper loads) then you have to make educated approximations of this missing information that will almost always be conservative. People always say, "it's not going to fall down, it's common sense, just look at it, others were built just like it and they are still standing". But if you can't prove it through applied scientific principles or scientific models, you can't just say its fine no matter how overkill it looks.

2) Time
For most of the designs that I work on, there are very short timelines for projects. These short timelines mean that there is not enough time to do proper analysis on the entire structure so some vary broad assumptions get made. And the broader the assumption, the more conservative it has to be. The less time that is available to analyze, the more excessive the design becomes

3) Code
Specifications like the ANSI/AISC 360, CSA S16, ACI 318, CSA A23 which get incorporated into building codes specify exactly what strengths you are allowed to assign to members. Given that inelastic and plastic analysis is allowed to be used, time often only permits the use of linear elastic analysis in my case. This is one item that always gets brought up. In a linear elastic analysis the member fails, but in reality the forces will be redistributed throughout the structure to different members. If you don't have the time, tools, or expertise to do more complex analysis, and you are stuck with first order linear elastic, you can't rely on the force being redistributed, because you can't show it.
 
Replies continue below

Recommended for you

I'm not sure what your ethical requirements are for the PE exam, but ethics aren't something you can opt into later on
Ethics are ethics always
And besides, if they haven't respected the engineer's role up to now, do you really think they will suddenly stop the gravy train just because you got your PE?
Up to you mate, it is a tough spot.

 
I've only had two instances of this.

One was a processor processing lab outside Ottawa. The project manager didn't think I needed rock anchors to secure the stairwells and was friends with one of the plan examiners. The plan examiner wanted my calculations. He was happy with the design, except he wanted the top 10' of the rock anchors sleeved. They weren't pre-tensioned... so it didn't make any difference.

The other was a auto plant in Windsor where a 32' dia VOC duct system was added to the roof. The columns had to be reinforced. They were 60' or 80' long (I no longer recall). I'd reinforced them by adding plates across the toes of the existing W sections rather than reinforce the flanges. A few of the plant engineers asked why I'd reinforced across the toes and I explained that it improved the buckling strength... and they were happy with that. It wasn't just one, it was a few. We missed out in providing the VOC design because the manager of the mech component couldn't be bothered to call him back because he didn’t know who he was. It was one of those projects where everything went very well.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik
 
I think us engineers have spent excessive time discussing this issue with clients and builders, especially the bad ones who devalue what we do and only care about getting a stamp.

As much as the codes that we're required to follow are not perfect, when our work is being questioned (especially when we're accused of over-designing), the codes are our best friend. In this situation, I simply tell people that I'm required to provide the structural design in accordance with the required codes, and I don't really have a choice in the matter. If that's not a satisfactory enough response, I might break it down further, explaining what the required loading is (and how those loads are unlikely to occur). I like to explain how many people it would take standing on their living room floor, for example, to realize a live load of 40 psf.

Beyond that, I might send some basic structural calculations, or refer them to a table in the IRC/IBC, like if somebody is trying to tell me how their 2x4 roof rafter spanning 20 ft is totally fine because the roof hasn't collapsed yet. Sometimes I'll get a builder explaining how some other engineer will let them do something that I won't allow. In that case, I ask them to ask the other engineer for my permission to review their plans showing this thing that they allow and I don't. Unsurprisingly, nobody ever follows up with that.

People asserting that a structure or portion thereof is overkill don't actually know, and unless they also happen to be the engineer stamping the design, they have nothing to lose in making an uninformed statement like that.

Finally, buildings just don't collapse enough that it's acknowledged as a real risk by the general public. They're kind of like airplanes in that sense. Very unlikely to fail, but when they do, it's very, very bad. I wonder if there are also people complaining about airplanes being overdesigned.
 
@ENG16080 agreed, you get a bit sick of trying to justify stuff after a while
Some go to's for me now

1) Ask someone whether they have any suggestions for how it could have been done better
Usually it's just "make it smaller" or something equally dumb, in which case you can just fall back on Code
They also know it's a pretty weak statement and making them say it out loud forces them to confront the knowledge gap - they have no idea how this thing could have been 'designed smaller'

2) When someone gives you the old "I know other engineers that would do XYZ differently/better/cheaper"
I default to "I can't speak to the actions of other engineers but my job is to design it Code and that's what I've done"

3) Occasionally you get people with a genuine interest or concern and they will listen to a proper explanation
Often showing them actual calculations, or doing the design in front of them, or talking through the process with them will satisfy them
 
matty54 said:
The way the business is run is a result of "the machine" that everyone has become a cog in since its start. There has been so much profit made throughout the years as a result of being able to produce so quickly without the red tape that so many other industries would have to deal with, it is impossible for those at the top running the machine to say "yes lets go backwards and loose all this profit and charge the clients so much more money and time and become less desirable as a company" even if they were aware of all the corners that were being cut (I'm not saying they are or are not aware). But it would take something vary drastic happening to change the momentum of the machine.
Many disasters follow this exact blueprint.

Concerning the engineering work that you currently perform at this company, you should do every design as though you are the person stamping it. It sounds like you're too good for this place. A place like this will likely continue to cut corners until there's finally a disaster at which point they'll be looking for somebody to blame (like your boss and you).
 
Good point Greenalleycat,
I believe the "no grey area in ethics" debate could be a whole other conversation.
 
Greenalleycat, your point 3) is exactly the kind of client that I like to work with.
 
Typically, I ask them to provide an example of what they want to do and show me where it was done. Then ask them if they are willing to get a license and seal the project. Additionally, ask them if they are willing to sign a letter waiving your liability saying they will cover any legal issues that may arise for life. The answer to all of these is almost always no. Then I explain to them that I agree, there is conservatism built into the codes, I agree that building over there has this and hasn't fallen in 100 years, but that doesn't mean it meets current code which I am bound by law/jurisdiction to meet. That is usually the end of the discussion. If I really like the person I'm talking too, I'll actually take the time to walk them through some design aspects and show them why something was the way it was, for instance, recently I was asked why do I place PEMB foundations a few feet down, I went through the calc with them sketching how if I bury the footing I can utilize the weight of soil above the footing at the soil friction angle which means they can reuse some site soils and have less concrete, both of which save significant money.
 
I tell non-engineers what I believe to be the truth:

There's what I think works and there's what I can prove works. As a licensed professional with ethical obligations to my community, the latter is my domain.

This often leads to the "but nothing ever fails" critique. If I have pen and paper handy, I do the sketch below and illustrate why that is the case, by design. If they get it, great. If not, it often serves as a conversation ender anyhow.

Realistically, in my opinion, a prudent business person calibrates their designs to fall near the median level of rigor for local practice. The perception of "over design" is often relative to our competitor's designs, past and present.

Unfortunately, I think that one really does have to do what the Romans do when in Rome for the most part. So you:

a) calibrate OR
b) find different space OR
c) accept constant stress and frustration OR
d) make peace with very slow, incremental change.

c01_dgeoxx.jpg
 
WesternJeb said:
I constantly agree with them how overdesigned and silly it is for us, but the code is the code that we have to follow.

I'm sure that we've all done a bit of that when wearing our salesman hats. At the same time, I feel that such an approach serves to undermine our entire profession.

For the most part, I very much doubt that you have any rational basis for questioning the reliability targets established in our design standards. I know that I don't.

By sleeping with the enemy, so to speak, we waste opportunities to educate our clients and to promote the legitimate value of our services. We also undermine one another.
 
matty54 said:
Good point Greenalleycat,
I believe the "no grey area in ethics" debate could be a whole other conversation.

Most of us know what the situation your currently in feels like. At the end of the day you can only control your own actions. If you don't get the final say on something because of your company structure, so be it. But you should at least have your say. Your responsibility is to expeditiously voice your concerns, document them.

It is possible to be ethical under such circumstances, but it may compromise your ability to continue working for this employer.

This outcome, may well be the best one for you. Like others have said, this company is an old dog, and it is unlikely that you will see any improvement in this behavior. Try to visualize what good outcome you could possibly expect by staying untill you get your Peng.

In the meantime document your concerns, and polish up the old resume.
 
matty54 -
a) I hope you have a PE overseeing your work there so you can claim that on your PE application when time comes; if not, then you have a another problem
b) You should be looking for another job now; this current situation sounds very bad, is not good for your training or career growth, and is likely not good for your health due to the added stress being imposed on you
c) Good luck
 
One of the people I work for is in the pressure vessel end of things. So he's very accustomed to pressure vessels requiring a 3.5 factor of safety. Meaning, if you build the same vessel with a 2.0 FOS, it probably wouldn't blow up, but wouldn't meet the code, either. So that's a good analogy to explain some other building-code related ideas. (Example: tanks that have stood there for 40 years unanchored, but would require anchorage under current standards.)

Another approach is "That building's been there 40 years, and it hasn't fallen over YET." That doesn't mean it won't! The "don't build 'em like they used to" buildings are the ones that remain, not every building ever built.

Sometimes on the ethical ideas, it is helpful just to point out that it IS an ethical lapse. "We could do this, but it wouldn't be ethical" is better than "We probably shouldn't do this."
 
Aesur said:
Typically, I ask them to provide an example of what they want to do and show me where it was done. Then ask them if they are willing to get a license and seal the project.
Ok, I got a laugh out of that. I need to remember this one!

WesternJeb said:
I constantly agree with them how overdesigned and silly it is for us, but the code is the code that we have to follow.
I don't mean to gang up here and I have in fact said similar things to clients in the past, but I agree with KootK. Our codes are immensely valuable. They're the culmination of endless research, in a continuous state of recalibration as problems/disasters occur. While I feel that the codes have in some cases become complicated to the point of defeating some of their value, I still wouldn't want to be involved in this profession if these codes didn't exist. They provide consistency amongst us which strengthens the legitimacy of the profession.

Imagine the total dumpster fire, train wreck this profession would be without having codes to fall back on. We would have to justify every f'in thing to every other builder and client we work with. The number of "engineers" designing well beyond safe limits to save the big developer, company shareholders, or whoever a buck would be much worse than it currently is. Those of us not willing to push the limits would just get pushed out of business. This would be a total disaster.
 
We've sown an ugly situation for ourselves in Alberta that is coming home to roost.

For ever and ever, we've laughed with contractors about the "Imaginary Alberta Earthquake" that will never happen. Trouble is:

- Vancouver gets it's 9.50 EQ
- Calgary gets it's 4.20 EQ
- The likelihood of Calgary getting it's 4.20 in any given year is the same as Vancouver getting it's 9.50.

So the risks of crap design in Calgary for a 4.20 are pretty much the same as they are in Vancouver for a 9.50. Those two events have been calibrated to represent equal hazard risk.

Our code writers have finally had enough of our faux-aseismic bullshit and are starting to enforce proper detailing and design to bring Alberta up to, at least, 2nd world standards of care.

Nobody's gong to be laughing much next year when folks start pricing expensive lateral systems for seismic loads that we've all be mocking as "imaginary" since 1970. And, of course, there will be a wild variation in the rate at which local firms elect to properly implement the new requirements. Market chaos.

Give me a code that requires excellence and enforce it. Meaningful peer review and real consequences. As far as design efficiency goes, I'm happy to go toe to toe with anyone exercising a comparable level of care.
 
These people are rarely convinced for the simple fact they can go find someone that will be more agreeable. What I do not understand is why you stay? Is the pay awesome? No other work? They do not support you very well, and this does not generally get better. We have watched survey and mech engs start into structural work to stabilize their workflow. Many find some remote worker and the quality of work is usually terrible. They are cheap, so they attract a certain type of client.
 
The code requires us to design for a multitude of different scenarios comprised of simultaneous loadings and load effects. The likelihood that some of these scenarios ever actually occur is immeasurably small.

Perception be damned, as structural engineers this is the standard of care we are bound to.
 
Clients and contractors are generally opposite mind set of engineers. The quantity vs quality relationship is a tug of war.
Clients/contractors want quantity cause that churns profit. not too concerned on quality. Barely passing in terms of quality is definitely OK in a lot of scenarios. Especially when $$$ is in mind.
Engineers want quality. Pumping out quantity work with low quality can make it hard to sleep.

 
Koot, doing an oil sands project in a poor site class where the seismic can actually start to be a consideration is a fun adventure where entire meetings of people get mad at you for even suggesting it.

 
Seppe said:
The likelihood that some of these scenarios ever actually occur is immeasurably small.
On the contrary, in the event these scenarios did occur, our building codes provide the minimum level of care we have to adhere to in order to stay within the confines of the law. I don't know about you all, but sometimes the minimum of anything is not enough to me. Especially when you look at some of the prescriptive designs in the building codes.

I've seen my share of work in jurisdictions prone to hurricanes, floods, tornadoes, and water infiltration. Not only is there a major concern for the life safety, but these structures can be so damn expensive that serviceability is likely to be a major problem. You could end up in litigation for something as trivial as facade distress.

Even worse, the improper design for serviceability and lack of maintenance can lead to a catastrophic event. I understand this is something different from industrial work (mentioned in the OP). But nevertheless, the design codes we follow are one link in a very long chain that comprises the construction of a building. If you consider every corner and hole poked into the process, you're likely NOT getting anything close to the final product you anticipated would occur. Example, a material was ordered incorrectly, concrete mix was done incorrectly, structural elements were placed incorrectly, inspectors didn't catch some things, "by others" is called upon and is a no show, and other design professionals cut the same corners as their peers... you catch the drift. Each small modification, no matter how insignificant, stacks up. We have the chance to be the strong link in a rather questionable chain.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor